As Father David Kuetner explained in a homily at St. Peter Chanel Catholic Church (Sunday, June 17, 2012), Jesus taught so much in parables because life is itself a parable.  A parable is a story about something that we are familiar with (such as a merchant in search of fine pearls) that is meant to point to something else more mysterious (the kingdom of God) (see Matthew 13:45-46).  Everything in this life can help us learn about God–a gift that is meant to point us to the Giver.  Jesus taught in parables to orient us to that reality.